<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        .container{
            width: 1000px;
            margin-left: auto;
            margin-right: auto;
            background-color: red;
            overflow: hidden;
        }
        .container div{
            width:240px;
            height:300px;
            border:1px solid #333;
            float: left;
            box-sizing: border-box;
        }
        /* .container div:not(:nth-child(4n+4)){
            margin-right: 13.3333px
        } */
        .one{
            margin-right: 13.3333px;
        }
    </style>
</head>
<body>
    <div class="container">
        <div class="one"></div>
        <div class="one"></div>
        <div class="one"></div>
        <div></div>
    </div>
</body>
</html>